GLOSSARY - L
| Launcher | rocket designed to lift one or more spacecraft from the surface of the Earth into space (usually into orbit) | | L band | frequency range from 0.5 to 1.5 GHz | | Leased line | one or two-way connection leased from a telecommunications operator for a long period, often one or more years; leased lines are usually analogue, but the expression is sometimes used for digital connections | | Link budget | standard way of calculating the performance that can be achieved by a particular link | | Liquid propellant | the liquid fuel and oxidiser used in most rockets; liquid propellants are generally classified as being "storable" which can be stored at room temperature or "cryogenic" which are liquefied gases; examples are: storable fuels - UDMH and hydrazine, cryogenic fuels - liquid hydrogen (LH2), storable oxidiser - nitrogen tetroxide, cryogenic oxidiser - liquid oxygen (LOX) | | Little LEO | low earth orbit satellite for only data communications | | Local Area Network (LAN) | network covering a limited geographical area, often only a single site or building, used to connect together computers at data rates of between 1 to 100 Mb/s. | | Local loop | connection between a telephone exchange and a subscriber | | Low Earth Orbit (LEO) | an orbit of altitude between 200 and 1000 km above the Earth | | Low Noise Amplifier (LNA) | a preamplifier, generally located as near to the antenna feed as possible, which has a very low noise figure and which is used to boost the receive signal level for transmission across the site to the receiver(s); ensures that signals are received with the minimum of additional noise | | Low noise block downconverter | a combined low noise amplifier and downconverter in a single device which is mounted on an antenna feed | | Luminance | the part of a television signal carrying the brightness information |
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